Both thermo-optical and electro-optical components are known. The working of thermo-optical components is based on the phenomenon of the optical waveguide material employed exhibiting a temperature dependent refractive index. Polymeric thermo-optical components generally comprise a polymeric three-layer structure on a substrate. The three-layer structure comprises a low refractive index lower cladding layer, a high refractive index core layer, and a low refractive index upper cladding layer. On top of the upper cladding layer heating elements are provided (usually metal strips) to heat the polymeric cladding material, in order to change the refractive index for switching. The working of electro-optical devices is based on the phenomenon of the non-linear optically active material employed exhibiting an electric field dependent refractive index. Polymeric electro-optical components in general also comprise a polymeric three-layer structure. The three-layer structure comprises a low refractive index lower cladding layer, a non-linear optically active, high refractive index core layer, and a low refractive index upper cladding layer. On top of the upper cladding layer electrodes are provided to apply an electric field to the non-linear optically active material to change the refractive index for switching.
U.S. Pat. No. 5,113,471 discloses a three layered structure as described above, which is additionally provided with a reinforcing layer on both sides.
EP 642 052 claims a polymeric thermo-optic device comprising a polymeric guiding layer sandwiched between two cladding layers of lower refractive index than the guiding layer, wherein the upper cladding layer (carrying the heating element) has a lower refractive index than the lower cladding layer (contacting the substrate to which the three layered structure is attached).
The known optical components still suffer from extensive light loss; moreover, in the thermo-optical components the switching speed is not optimal, while in the electro-optical components the switching efficiency leaves much to be desired.
The present invention alleviates these problems.